TheworkofmathematicianRogerPenroseintheearly1970s,onthegeometryofwhatarecalledaperiodictiles,turnedouttodescribethearchitectureofapreviouslyunknownclassofcrystals.（）
(A)whatarecalledaperiodictiles,turnedouttodescribe
(B)whatiscalledaperiodictiles,describes
(C)aperiodictiles,describing
(D)so-calledaperiodictiles,describe
(E)aperiodictiles,itturnedouttodescribe